Saving Electricity with a Transformer Upgrade


Transformers are essential for electricity distribution, that step up and down the voltage as it passes from power plants to individual buildings. With a typical efficiency rating of above 97%, they have proved themselves to be the most efficient electrical devices. You must keep that in mind that they are always operational even when the load linked to them is small. This is the reason why even a small gain in the transformer efficiency can save thousands of dollars over time.

The US Department of Energy has finalized the latest transformer efficiency standards that came into effect in January 2016. Although these standards never force building owners to improve their transformers, all units manufactured since then have to fulfill the minimum efficiency values mentioned in the standard.

These types of transformers cover the following

  • Low-voltage dry-type transformers
  • Medium-voltage dry-type transformers and
  • Liquid-filled distribution transformers

Low voltage dry type transformers are best suited for building owners as these units are commonly seen indoors. The rest of the transformers are used to keep the distribution voltages down and mainly seen at the main service connection.

Decrease the power consumption of your building

In case you have old transformers at your building, replacing them for newer models can be an effective measure to reduce energy consumption. For better results, you can measure the total harmonic distortion (THD) of your electrical system and add the corresponding filters. Loads with high harmonic content decrease the efficiency of Transformers.

DOE 2016 Efficiency Levels for LVDT Transformers

LVDT transformers are commonly found in facilities that manage various voltage levels, like 480/277 V and 220/127 V. The minimum efficiency for three phase models was improved with the DOE 2016 standard. There has been no such improvement in the efficiency of single-phase models but it is now being specified with two decimals.

Efficiency Requirements for Single-Phase, Dry-Type, Low-Voltage Transformers

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Efficiency Requirements for Three-Phase, Dry-Type, Low-Voltage Transformers

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If you have single-phase transformers that fulfill the previous standard (TP-1), upgrading to DOE 2016 efficiency units will not bring any remarkable change in your energy consumption. However upgrading three phase transformers in buildings that have many of them can improve your savings to a great extent.

You can expect a wide variety of kVA ratings and efficiency levels in a facility that has multiple LVDT transformers. A professional energy audit can help you recognize the most effective upgrades that you can prioritize. Consider that other energy efficiency measures are capable of decreasing the load on transformers. For instance it is possible to reduce power consumption by 60 kW if 200 HID lamps that consume 450W each is upgraded to 150W LED fixtures. If this lighting system has an old dedicated transformer, replacing it can increase efficiency and decrease kVA rating.